A collaboration between composer Michael Pisaro and AMM guitarist/improviser Keith Rowe, with each bringing scores which they improvised over, creating 13 discrete sections including samples from Shostakovich's 13th String Quartet, balancing activity, space and silence in patient ways that only two such experienced composer/improvisers could.

"On this two-and-a-half hour, semi-improvised opus, the two guitarists and composers approach finely wrought detail and vast empty space in ways that can warp one's perception of time itself.

The first recorded collaboration between veteran guitarists Keith Rowe and Michael Pisaro is dauntingly ambitious. Before making a note of music, the pair decided 13 Thirteen would last 140 minutes. They each separately wrote and recorded scores, then improvised together along with those pre-recorded elements. Pisaro's score includes four samples from Shostakovich's 13th String Quartet, each occurring three times in 10-minute intervals, and the composition is divided into 13 discrete sections. As if to emphasize their ambition, Rowe calls his own score "Fate" and his half of the improvisation "Life" (a reference to Russian author Vasily Grossman's novel Life and Fate).

Absorbing those concepts along with nearly two-and-a-half hours of music might seem like a formidable task. But as a listening experience, 13 Thirteen is far from intimidating. There is a lot of space and near-silence here; that's often the case with the kind of music that Rowe and Pisaro each make and that Erstwhile frequently releases. But 13 Thirteen also offers plenty of warmth and detail. Even when they get busy or loud, the sounds the two musicians make are patient and resonant. Once your ears acclimate to their long-form approach, the vibration of a single guitar string can sound both welcoming and monumental.

The momentousness of Rowe's playing comes from a long career of study and practice. The English-born 77-year-old, known best for his work with pioneering British group AMM, has heard and made so much music that every improvised sound he creates-usually with tabletop guitar and electronics-is informed by layers of history. Pisaro brings a lot to the equation too, as a prolific player, collaborator, composer (he has written over 80 scores, many published by Germany's Edition Wandelweiser), and professor currently teaching at California Institute of the Arts.

All of this combined experience is clear on 13 Thirteen, especially in the way each sound fits into an evolving narrative. Every choice is distinct and measured, giving the listener ample time to contemplate it and connect it with what came before. Rowe and Pisaro are like tour guides for their own sonic worldviews, never rushing you but also never lingering too long. That might sound facetious, given how lengthy and sparse 13 Thirteen is, but focused attention reveals that even the most gradual sections continually move forward.

Despite the album's weighty classical influences, you don't need much prior knowledge to track the piece's recurring motifs. The way the string samples, guitar plucks and strums, and Rowe's harsher, metallic sounds periodically surface gives 13 Thirteen the feel of wordless verse, filled with subtle rhymes and complex rhythms. This effect is aided by the intense clarity of the recording. Even the softest sounds are sharp and detailed, making everything refreshingly concrete and life-like, especially for music that could be called abstract.

As Rowe and Pisaro's motifs build, 13 Thirteen becomes physically and emotionally affecting, and in the right frame of mind, it can slow you down, warping and even dissolving your internal clock. More subtly, 13 Thirteen will likely stretch your understanding of improvisation. Free-form music often toggles between bracingly abrupt moments and placid stretches where players spin wheels before regaining momentum. But Rowe and Pisaro find a middle path where all sounds are surprising yet none are shocking. Following their interplay is like taking a meditative roller coaster ride. By working their craft in such a thoughtful, considered manner, Rowe and Pisaro open up space, both within their music and within anyone who chooses to listen."-Marc Masters, Pitchfork Media